The present invention relates to a method of measurement of suprasystolic waveforms from an upper-arm blood pressure cuff. The analysis and interpretation of these waveforms can be performed directly on the measured and processed signals. It has been demonstrated that the suprasystolic waveform changes significantly and predictably with the administration of vasoactive agents, physiological challenges, normal ageing processes and morbidities.
Recent literature has noted the potential importance of central blood pressure (waveform and values such as systolic, diastolic and mean) in the management of cardiovascular risk. To that end, it would be advantageous to be able to estimate central pressures.
More particularly, the invention relates to methods of physics-based modelling of the waveform measurement system and the arterial system being studied. One of the early models of this kind, constructed by Joe El-Aklouk at the Institute of Biomedical Technologies, Auckland University of Technology, was based on acoustic pressure wave propagation in tubes.
El-Aklouk's work involved the development of models to simulate wave propagations given known material properties, geometry, end conditions and driving inputs. El-Aklouk also studied the transmission of pressure oscillations in an artery to an externally applied inflatable cuff.
More recent models have been proposed by Berend Westerhof et. al. (Am J Physiol Heart Circ Physiol 292:800-807, 2007.) who examined the pressure transfer between the subclavian root and unoccluded brachial artery assuming that the more peripheral arteries present a known end-impedance. In another recent paper (J Appl Physiol 105:1858-1863, 2008), Westerhof et al. attempt to show that changes in impedance caused by changes in the peripheral circulation have a negligible effect on the central pressure prediction. Westerhof et al. do not consider the use of a suprasystolic cuff to isolate the brachial artery from the peripheral circulation.